CN111166994A

CN111166994A - Sleeve assembly and instrument transportation system comprising same

Info

Publication number: CN111166994A
Application number: CN202010085482.0A
Authority: CN
Inventors: 林林; 程增兵
Original assignee: Shanghai Huihe Healthcare Technology Co Ltd
Current assignee: Shanghai Huihe Healthcare Technology Co Ltd
Priority date: 2020-02-05
Filing date: 2020-02-05
Publication date: 2020-05-19

Abstract

The present application provides a cannula assembly and a device transportation system including the cannula assembly, and the device transportation system including the cannula assembly includes: a first control elbow, which has: a first tube body, a second tube body, a first pull wire, which is embedded in the first pipe body and the second pipe body; and a second control bend pipe, which has: a third pipe body, a fourth pipe body; and a second pull wire, which is embedded in the first pipe body The third pipe body and the fourth pipe body are used to adjust the bending degree of the third pipe body and the fourth pipe body in the first control bend pipe; wherein, the outer diameter of the second control bend pipe is smaller than the The inner diameter of the first control bend pipe, and the friction force between the outer surface of the second control bend pipe and the inner surface of the first control bend pipe is sufficiently small; by controlling the second control bend pipe in the first control bend Moving and rotating in the tube and controlling the first and second pulling wires to adjust the combined shape of the first and second bending control tubes in three-dimensional space.

Description

Sleeve assembly and instrument transportation system comprising same

Technical Field

The present disclosure relates to the field of medical devices, and more particularly, to a cannula assembly for interventional therapy and a device transportation system including the same.

Background

Structural heart disease refers to the anatomical change of blood vessels and the physiological change of cases caused by the change of the internal tissues of the heart and the blood vessels generated by the internal tissues of the heart due to anatomical abnormality, and comprises congenital, valvular heart disease, cardiomyopathy and macrovascular disease.

The traditional treatment of structural heart disease mostly adopts a surgical open chest mode, and the operation generally needs the aid of extracorporeal circulation, and patients with older ages are generally difficult to tolerate and are easy to have various related complications. With the development of minimally invasive interventional techniques, structural heart diseases have emerged in recent years with a number of minimally invasive interventional treatment solutions, including replacement and repair-type instruments, which have been emerging, and thus new options have been provided for patients who have difficulty in tolerating surgical thoracotomy.

Such techniques, represented by aortic valve replacement, are most rapidly developing and are becoming mature. For the diseases related to the mitral valve and the tricuspid valve, due to the special anatomical structure, the accurate arrival and function realization of the replacement valve position can be realized by the simple guide wire guidance which is difficult to realize like the aortic valve. Some semi-invasive instruments, still open chest in nature, have thus appeared, still by means of a semi-open chest approach, by transapical or transatrial, still with the associated complications and slow recovery after surgery.

In view of the above, how to overcome the limitations of the prior art and achieve a true transvascular approach for treating structural heart diseases, especially diseases related to valves with special anatomical structures of mitral valve and tricuspid valve, is a technical problem to be solved by the present application.

Disclosure of Invention

In view of the above problems, it is a primary object of the present application to provide a cannula assembly and an instrument delivery system including the same, the cannula assembly having a bi-planar bending control system, which can be used in the field of structural cardiology interventions, the cannula assembly being capable of passing an instrument through a transvascular approach to a designated cardiac anatomical location, enabling repair or replacement of the instrument to a target location, of an already existing instrument.

The present application provides a sleeve assembly, this sleeve assembly includes:

a first trap having:

a first tube disposed at a distal end of the first bend control tube, the first tube having a first hardness I,

a second tube disposed at a proximal end of the first bend control tube, the second tube having a second hardness II, wherein I < II, and

the first pull wire is embedded in the pipe walls of the first pipe body and the second pipe body and is used for adjusting the bending degree of the first pipe body relative to the second pipe body; and

a second trap having:

a third tube disposed at a distal end of the second bend tube, the third tube having a third hardness III, wherein III is less than I,

the fourth pipe body is arranged at the near end of the second control bend pipe and has a fourth hardness IV, wherein III is less than IV; and

the second pull wire is embedded in the pipe walls of the third pipe body and the fourth pipe body and is used for adjusting the bending degree of the third pipe body and the fourth pipe body in the first control bend pipe;

the outer diameter of the second control bend pipe is smaller than the inner diameter of the first control bend pipe, and the friction force between the outer surface of the second control bend pipe and the inner surface of the first control bend pipe is small enough, so that the second control bend pipe can freely move and rotate in the first control bend pipe along the axial direction and the circumferential direction respectively;

the combined shape of the first controlled bending pipe and the second controlled bending pipe in the three-dimensional space is adjusted by controlling the second controlled bending pipe to move and rotate in the first controlled bending pipe and controlling the first pull wire and the second pull wire.

Optionally, adjusting the combined shape of the first pipe and the second pipe in the three-dimensional space further includes adjusting the combined shape of the portion of the third pipe exposed to the first pipe and the first pipe in the three-dimensional space.

Optionally, the first hardness I is 30-35D, the second hardness II is 60-72D, the third hardness III is 25-30D, and the fourth hardness IV is 60-72D.

Optionally, the first hardness i is 30D, the second hardness ii is 72D, the third hardness iii is 25D, and the fourth hardness iv is 65D.

Optionally, the cannula assembly further comprises:

the first handle is connected with the second pipe body and the first pull wire and used for controlling the axial movement distance of the first pipe body and the second pipe body and adjusting the bending degree of the first pipe body relative to the second pipe body; and

and the second handle is connected with the fourth pipe body and the second pull wire and is used for driving the fourth pipe body and the third pipe body to move in the first control bend pipe along the axial direction or driving the fourth pipe body and the third pipe body to rotate in the first control bend pipe and adjusting the curvature of the third pipe body exposed to the first pipe body.

Optionally, the distal ends of the first tube and the third tube are respectively provided with a pull wire ring, which is respectively connected with the first pull wire and the second pull wire for controlling the movement of the pull wires.

Optionally, the first pulling wire and the second pulling wire respectively include 2 pulling wires, the 2 pulling wires are symmetrically distributed on the first controlled bending pipe and the second controlled bending pipe, the distal ends of the 2 pulling wires are connected to form 2 protrusions, the pulling wire ring forms 2 grooves, the grooves and the protrusions are matched with each other, and the maximum diameter of the protrusions is greater than the distance between the 2 pulling wires.

Optionally, at least one of the outer surface of the second bend control tube and the inner surface of the first bend control tube has a slip layer so that the friction between the outer surface of the second bend control tube and the inner surface of the first bend control tube is sufficiently small.

Optionally, the difference in hardness between the third tube and the first tube is such that bending of the portion of the third tube exposed to the first tube does not substantially affect bending of the first tube; the hardness difference between the first tube and the second tube enables the second tube to keep linear extension when the first tube bends; the hardness difference between the third tube and the fourth tube enables the fourth tube to keep linear extension when the third tube bends.

Optionally, the first tube and the third tube respectively include joint elements formed by connecting a plurality of joint units N to each other in the circumferential direction, each joint unit N has a concave surface N1 and a convex surface N2 matching with the concave surface N1, and the joint elements are axially distributed in the tube walls of the first tube and the third tube.

Optionally, the proximal end of the fourth tube has a calibration mark for determining the length of the third tube 201 exposed to the first tube 101.

Accordingly, an embodiment of the present application provides an instrument transport system comprising a cannula assembly as in any one of the preceding claims and an instrument loaded onto the cannula assembly.

According to the technical scheme, the sleeve assembly provided by the application adjusts the combined shape of the first control elbow and the second control elbow in a three-dimensional space by controlling the second control elbow to move and rotate in the first control elbow and controlling the first pull wire and the second pull wire, so that the instrument can be conveyed to a specified position, and the instrument is adjusted to an angle suitable for repairing and replacing human tissues, so that the existing instrument can be repaired or replaced by the instrument at a target position.

In addition, the hardness difference between the third pipe body and the first pipe body enables the bending of the part of the third pipe body exposed to the first pipe body not to influence the bending of the first pipe body basically; the difference in hardness between the first tube and the second tube is such that when the first tube is bent, the second tube remains linearly extended; the hardness difference between the third tube and the fourth tube enables the fourth tube to keep linear extension when the third tube is bent, and the friction between the outer surface of the second control bend and the inner surface of the first control bend is small enough, so that the third tube and the first tube can be freely combined into a two-dimensional or three-dimensional shape in a three-dimensional space.

Drawings

In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings needed to be used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments described in the embodiments of the present application, and other drawings can be obtained by those skilled in the art according to the drawings.

FIG. 1 is a schematic view of a tricuspid valve repair device in accordance with an embodiment of the present cannula assembly, shown in use, being accessed through the jugular vein to a target location.

FIG. 2 is a schematic view of the present sleeve assembly in use in combination with a valve repair device.

FIG. 3 is a schematic view of the first and second control coils of the cannula assembly of the present application.

FIG. 4 is a schematic view of the third tube of the present ferrule assembly moving and rotating relative to the first tube.

Fig. 5A and 5B are schematic views of a pull wire ring of the present cannula assembly.

FIG. 6 is a schematic view of the tube construction of the present ferrule assembly.

FIG. 7 is a schematic view of the deployment of the tube body of the cannula assembly of the present application.

FIG. 8 is a schematic view of the present cannula assembly with the fourth tube having indicia marked on the proximal end.

Element number

1: a bushing assembly; 2: an instrument; 100: a first control bend pipe; 101: a first pipe body; 102: a second tube body; 103: a first pull wire; 200: a second control bend pipe; 201: a third tube; 202: a fourth tube body; 203: a second pull wire; 300: a first handle; 400: a second handle; 301. 401: pulling a wire ring; 1031,2031: projection 3011,4011: a groove; 204: and (5) scale marking.

Detailed Description

In order to make those skilled in the art better understand the technical solutions in the embodiments of the present application, the technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application, and it is obvious that the described embodiments are only a part of the embodiments of the present application, but not all embodiments. All other embodiments obtained by a person of ordinary skill in the art based on the embodiments in the present application shall fall within the scope of the protection of the embodiments in the present application.

In the present specification, the term "distal end" refers to an end of the first and second elbow control tubes that is distal from the first and second elbow control tubes when the operator manipulates the first and second elbow control tubes, and the term "proximal end" refers to an end of the first and second elbow control tubes that is proximal to the first and second elbow control tubes.

As shown in fig. 1 to 5, an embodiment of the present application provides a tube assembly 1, where the tube assembly 1 includes: the bending device comprises a first bending control pipe 100 and a second bending control pipe 200, wherein the first bending control pipe 100 is provided with a first pipe body 101, a second pipe body 102 and a first pull wire 103, the first pipe body 101 is arranged at the far end of the first bending control pipe 100, the first pipe body 101 is provided with a first hardness I, the second pipe body 102 is arranged at the near end of the first bending control pipe 100, the second pipe body 102 is provided with a second hardness II, I is less than II, and the first pull wire 103 is embedded in the pipe walls of the first pipe body 101 and the second pipe body 102 and is used for adjusting the bending degree of the first pipe body 101 relative to the second pipe body 102; the second trap 200 has: a third tube 201, a fourth tube 202 and a second pull wire 203, wherein the third tube 201 is disposed at a distal end of the second bend control tube 200, and the third tube 201 has a third hardness iii, wherein iii is less than i, the fourth tube 202 is disposed at a proximal end of the second bend control tube 200, and the fourth tube 202 has a fourth hardness iv, wherein iii is less than iv; the second pull wire 203 is embedded in the pipe walls of the third pipe 201 and the fourth pipe 202, and is used for adjusting the bending degree of the third pipe 201 and the fourth pipe 202 in the first bend pipe 100.

In one embodiment of the present application, the distal end of the third tube 201 of the sleeve assembly 1 carries a valve repair device, the sleeve assembly 1 is accessed to a designated anatomical location of the heart, such as a predetermined location of the tricuspid valve, by transvascular access (e.g., jugular vein, superior vena cava), and the valve repair device clamps the tricuspid valve and clamps two ends of the posterior valve of the tricuspid valve to bivalvate the tricuspid valve, so that the overall circumference of the annulus is shortened, thereby reducing the tricuspid regurgitation. It should be noted that the cannula assembly 1 is not limited to use in tricuspid valve repair, but may also be used in mitral valve repair, as well as for delivery of other devices.

The outer diameter of the second controlled bend pipe 200 is smaller than the inner diameter of the first controlled bend pipe 100, and the friction between the outer surface of the second controlled bend pipe 200 and the inner surface of the first controlled bend pipe 100 is small enough to allow the second controlled bend pipe 200 to freely move and rotate in the first controlled bend pipe 100 in the axial direction and the circumferential direction, respectively, and the friction between the outer surface of the second controlled bend pipe 200 and the inner surface of the first controlled bend pipe 100 is small enough to be achieved by coating at least one of the outer surface of the second controlled bend pipe 200 and the inner surface of the first controlled bend pipe 100 with a smooth layer, such as a PVP hydrophilic coating or any other suitable coating material, which is not limited herein.

The combined shape of the first and second controlled

bending pipes

100 and 200 in three-dimensional space is adjusted by controlling the second controlled bending pipe 200 to move and rotate in the first controlled bending pipe 100 and controlling the first and

second pulling wires

103 and 203. In an embodiment of the present application, adjusting the combined shape of the first bend controlling pipe 100 and the second bend controlling pipe 200 in the three-dimensional space now adjusts the combined shape of the portion of the third pipe 201 exposed to the first pipe 101 and the first pipe 101 in the three-dimensional space. Note that the three-dimensional space includes a two-dimensional plane.

As shown in FIG. 4, since the friction between the outer surface of the second bend control pipe 200 and the inner surface of the first bend control pipe 100 is sufficiently small, and the hardness III < I < II, and III < IV, the bending degree and the axial distance B of the third pipe 201 with respect to the first pipe 101 can be freely adjusted. When the axis of the third tube 201 and the axis of the first tube 101 are both located on the horizontal plane of the paper, the portion of the third tube 201 extending out of the first tube 101 forms a two-dimensional plane (i.e. the horizontal plane of the paper) combined shape with the first tube 101. When the axis of the first tube 101 is located on the horizontal plane of the paper, the axis of the third tube 201 rotates to form a certain angle, for example 90 °, with the horizontal plane of the paper, and the portion of the third tube 201 extending out of the first tube 101 and the first tube 101 form a three-dimensional combined shape. The free combination of the third tube 201 and the first tube 101 in the three-dimensional space can deliver the device to a designated position, including adjusting the device to a position and an angle suitable for human tissue repair or replacement, thereby achieving a better human tissue repair or replacement effect.

The first tube 101, the second tube 102, the third tube 201, and the fourth tube 202 may be made of Pebax and metal mesh, or may be made of other suitable materials, but the hardness gradient of the first tube 101, the second tube 102, the third tube 201, and the fourth tube 202 is sufficient to realize a free combined shape of the third tube 201 and the first tube 101 in a three-dimensional space, and the difference in hardness between the third tube 201 and the first tube 101 causes the bending of the portion of the third tube 201 exposed to the first tube 101 to substantially not affect the bending of the first tube 101; the difference in stiffness of the first tube 101 and the second tube 102 is such that when the first tube 101 is bent, the second tube 102 remains linearly extended; the difference in stiffness of the third tubular body 201 and the fourth tubular body 202 is such that the fourth tubular body 202 remains linearly extended when the third tubular body 201 is bent. Through a large number of experiments, the inventor finds that when the first hardness I is 30-35D, the second hardness II is 60-72D, the third hardness III is 25-30D, and the fourth hardness IV is 60-72D, the free three-dimensional combined shape of the third pipe body 201 and the first pipe body 101 can be realized. In another embodiment of the present application, the first hardness I is 30D, the second hardness II is 72D, the third hardness III is 25D, and the fourth hardness IV is 65D.

As shown in fig. 2, the present embodiment provides an instrument transportation system, which includes a sleeve assembly 1 and an instrument 2 mounted on the sleeve assembly 1, wherein the instrument 2 may be a holding instrument for heart valve repair or any other instrument suitable for transportation with the sleeve assembly 1. The cannula assembly 1 further includes: a first handle 300 and a second handle 400, wherein the first handle 300 is connected with the second tube 102 and the first pull wire 103, and is used for controlling the distance of the first tube 101 and the second tube 102 moving along the axial direction and adjusting the bending degree of the first tube 101 relative to the second tube 102; the second handle 400 is connected to the fourth tube 202 and the second pull wire 203, and is configured to drive the fourth tube 202 and the third tube 201 to move in the first elbow control pipe 100 along the axial direction, or drive the fourth tube 202 and the third tube 201 to rotate in the first elbow control pipe 100, and adjust a curvature of the third tube 201 exposed to the first tube 101. The structure of the first handle 300 and the second handle 400 is not limited to the structure shown in fig. 2, but may be any other suitable structure.

As shown in fig. 5A and 5B, in an embodiment of the present application, the distal ends (e.g., distal ends) of the first tube 101 and the third tube 201 are respectively provided with pull wire rings 301, 401, which are respectively connected to the first pull wire 103 and the second pull wire 203 for controlling the movement of the pull wires to adjust the bending of the third tube 201 and the first tube 101. First acting as go-between 103, second acting as go-between 203 and acting as go-between

ring

301, 401 can be the same or different materials, and first acting as go-between 103, second acting as go-between 203 and acting as go-between

ring

301, 401 can be processed into unsmooth matched with structure, and unsmooth structure welds through laser welding, promotes welding area to promote the power of binding of acting as go-between and acting as go-between ring.

As shown in fig. 6, in an embodiment of the present application, the first pulling wire 103 and the second pulling wire 203 respectively include 2 pulling wires, the 2 pulling wires are symmetrically distributed in the first bending control pipe 100 and the second bending control pipe 200, the distal ends of the 2 pulling wires are connected to form 2

protrusions

1031,2031, the shape of the

protrusion

1031,2031 may be similar to a semicircle, a quadrangle or any other shape, 2

protrusions

1031,2031 are embedded in the pipe walls of the third pipe 201 and the first pipe 101, the pulling wire rings 301, 401 form 2 grooves 3011,4011, the grooves 3011,4011 are matched with the

protrusion

1031,2031, the maximum diameter of the

protrusion

1031,2031 is greater than the distance between the 2 pulling wires, so that when the first pulling wire 103 and the second pulling wire 203 are pulled, the

protrusion

1031,2031 is clamped in the groove 3011,4011. When

protrusion

1031,2031 is semi-circular, "maximum diameter" refers to the diameter of the circle, and when

protrusion

1031,2031 is other shapes, "maximum diameter" refers to the maximum lateral distance of the protrusion perpendicular to the direction of extension of the 2 puller wires.

As shown in fig. 7, in an embodiment of the present application, the first tube 101 and the third tube 201 respectively include a plurality of joint elements N formed by circumferentially connecting a plurality of joint units N to each other, each joint unit N having a concave surface N1 and a convex surface N2 matching with the concave surface N1, and the plurality of joint elements are axially arranged and distributed in the tube wall of the first tube 101 and the third tube 201 to form a metal mesh. The design of the joint element can maintain the bending performance of the first pipe 101 and the third pipe 201, and simultaneously, the torsion resistance of the pipes is considered. In another embodiment of the present application, the distal and proximal ends of the first tube 101 and the third tube 201 are circular hole nets, the middle portion is an articulation element, and the circular hole nets are used for filling when the polymer material is coated and also used for enhancing the coating force between the layers of the first tube 101 and the third tube 201. In another embodiment of the present application, one or more axial reinforcing ribs can be added to the metal mesh along the axial direction for the purpose of axial deformation resistance.

As shown in fig. 8, in an embodiment of the present invention, the proximal end of the fourth tube 202 has a calibration mark 204 for determining the length of the third tube 201 exposed to the first tube 101, so as to provide identification for accurately regulating the length of the first tube 101 exposed to the third tube 201.

Finally, it should be noted that: the above embodiments are only used for illustrating the technical solutions of the embodiments of the present application, and are not limited thereto; although the present application has been described in detail with reference to the foregoing embodiments, it should be understood by those of ordinary skill in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some technical features may be equivalently replaced; and such modifications or substitutions do not depart from the spirit and scope of the corresponding technical solutions in the embodiments of the present application.

Claims

1. A block of bushings (1), characterized in that the block of bushings (1) comprises:

a first trap (100) having:

a first tube (101) disposed at a distal end of the first bend (100), the first tube (101) having a first hardness I,

a second tube (102) disposed at a proximal end of the first bend (100), the second tube (102) having a second hardness II, wherein I < II, and

a first pull wire (103) embedded in the wall of the first tube (101) and the second tube (102) for adjusting the curvature of the first tube (101) relative to the second tube (102); and

a second trap (200) having:

a third tube (201) disposed at a distal end of the second bend control tube (200), the third tube (201) having a third hardness III, wherein III is less than I,

a fourth tube (202) disposed at a proximal end of the second bend (200), the fourth tube (202) having a fourth hardness IV, wherein III < IV; and

the second pull wire (203) is embedded in the pipe walls of the third pipe body (201) and the fourth pipe body (202) and is used for adjusting the bending degree of the third pipe body (201) and the fourth pipe body (202) in the first control bend pipe (100);

wherein the outer diameter of the second controlled bend pipe (200) is smaller than the inner diameter of the first controlled bend pipe (100), and the friction between the outer surface of the second controlled bend pipe (200) and the inner surface of the first controlled bend pipe (100) is small enough, so that the second controlled bend pipe (200) can move and rotate freely in the first controlled bend pipe (100) along the axial direction and the circumferential direction respectively;

the combined shape of the first controlled bend pipe (100) and the second controlled bend pipe (200) in three-dimensional space is adjusted by controlling the second controlled bend pipe (200) to move and rotate in the first controlled bend pipe (100) and controlling the first pull line (103) and the second pull line (203).

2. A block of bushings according to claim 1, characterized in that adjusting the combined shape in three-dimensional space of the first and second control bends (100, 200) further comprises adjusting the combined shape in three-dimensional space of the portion of the third tube (201) exposed to the first tube (101) and the first tube (101).

3. A block of bushings according to claim 1 or 2, characterized in that the difference in hardness of the third tube (201) and the first tube (101) is such that bending of the portion of the third tube (201) exposed to the first tube (101) does not substantially affect the bending of the first tube (101); the difference in stiffness of the first tube (101) and the second tube (102) being such that the second tube (102) remains linearly extended when the first tube (101) is bent; the difference in stiffness between the third tube (201) and the fourth tube (202) is such that the fourth tube (202) remains linearly extended when the third tube (201) is bent.

4. A block of bushings according to claim 3, characterized in that the first hardness i is 30-35D, the second hardness ii is 60-72D, the third hardness iii is 25-30D and the fourth hardness iv is 60-72D.

5. A block of bushings according to claim 4, characterized in that the first hardness I is 30D, the second hardness II is 72D, the third hardness III is 25D and the fourth hardness IV is 65D.

6. A block of bushings according to claim 1 or 2, characterized in that the block of bushings (1) further comprises:

a first handle (300) connected to the second tube (102) and the first pull wire (103) for controlling the distance the first tube (101) and the second tube (102) move axially and for adjusting the bending of the first tube (101) relative to the second tube (102); and

and the second handle (400) is connected with the fourth pipe body (202) and the second pull wire (203) and is used for driving the fourth pipe body (202) and the third pipe body (201) to move in the first bend control pipe (100) along the axial direction or driving the fourth pipe body (202) and the third pipe body (201) to rotate in the first bend control pipe (100) and adjusting the bending degree of the third pipe body (201) exposed to the first pipe body (101).

7. A cannula assembly according to claim 5, characterized in that the distal ends of the first tube (101) and the third tube (201) are provided with a pull wire ring (301, 401), respectively, connected to the first pull wire (103) and the second pull wire (203), respectively, for controlling the pull wire movement.

8. A block of tubes according to claim 7, wherein the first pulling wire (103) and the second pulling wire (203) each comprise 2 pulling wires, the 2 pulling wires are symmetrically distributed in the first bending control tube (100) and the second bending control tube (200), the distal ends of the 2 pulling wires are connected to form 2 protrusions, the pulling wire ring (301, 401) forms 2 grooves, the grooves and the protrusions are matched with each other, and the maximum diameter of the protrusions is larger than the distance between the 2 pulling wires.

9. A block of bushings according to claim 1 or 2, characterized in that at least one of the outer surface of the second bend (200) and the inner surface of the first bend (100) has a slippery layer so that the friction between the outer surface of the second bend (200) and the inner surface of the first bend (100) is sufficiently small.

10. A cannula assembly according to claim 1 or 2, wherein the first tube (101) and the third tube (201) respectively comprise articulation elements formed by a plurality of articulation units N connected to each other circumferentially, each articulation unit N having a concave surface N1 and a convex surface N2 cooperating with the concave surface N1, the articulation elements being axially distributed in the wall of the first tube (101) and the third tube (201).

11. A block of bushings according to claim 1 or 2, characterized in that the proximal end of the fourth tube (202) has a graduated marking (204) for determining the length of the third tube (201) exposed to the first tube (101).

12. An instrument transport system, characterized in that it comprises a sleeve assembly (1) according to any one of claims 1 to 11 and an instrument (2) loaded on the sleeve assembly (1).